A record number of poor families shivering through this winter’s cold snap have applied for charity vouchers to keep their homes warm, amid a spate of deaths from toxic fumes from makeshift heaters.

St Vincent de Paul has blamed rising electricity prices for the string of tragic carbon monoxide poisonings as a top NSW firefighter said officers had seen widespread use of dangerous improvised heaters, with residents in several states resorting to bringing BBQs or gas cookers inside their homes in a desperate attempt to keep warm.

Firefighters have also encountered residents placing bolted-together terracotta pots together over LPG heaters, or warming their homes by leaving oven doors open.

Such jerry-rigged heaters can produce enough toxic carbon monoxide gas to render people unconscious within minutes.

Fire and Rescue NSW Assistant Commissioner Mark Whybro told The Huffington Post Australia he had never before seen such dangerous behaviour, prompted by a perfect storm of arctic conditions and rising power costs.

“It’s not something we’ve really been exposed to in the last few years -- there has been a spike this year. The trend, we think, is around people believing energy prices are high and looking for alternatives.”

Helena Curic and Derek Kehler died in June after leaving a woodchip fire burning in their cabin (Fairfax/Supplied)

Chris Barber, community development coordinator with the Country Fire Authority, said Victorian firefighters had also noticed the alarming trend.

"I'm not aware of all those incidents, but it doesn't surprise me. We do see those sorts of practices occurring, even in commercial locations, such as kitchens bringing in an LPG cooker as a supplementary cooking device," he said.

"We do see those sorts of risks, but people may not see that as a risk so we do give messaging to the community around those sorts of dangers."

Felicity Gamble, climatologist with the Bureau of Meteorology, said this winter had seen the most cold nights since at least 2002.

“In Sydney, we’ve felt the impact of several cold spells that would normally come maybe once a year or once every few years,” she said.

“We’ve had the most cold nights, nights below eight degrees, since 2002. It’s been a long spell of cold nights, especially as the last few winters have been close to average.”

Ajantha Navarathinam, of Greystanes NSW, who died after placing a frying pan full of heated BBQ heat beads next to his bed;

Helena Curic and Derek Kehler, who died at a cabin near the Blue Mountains, NSW, after going to sleep with a woodchip fire burning in their cabin;

A man in Ararat, Victoria, who died after using an LPG bottle and outdoor heater to heat his home;

A family of four who were taken to hospital after using barbecue coals to heat their Bankstown, NSW unit;

Another family of four who presented to hospital in a serious condition after using an open charcoal burner to heat their Penrith, NSW home;

Three women and a 15-month-old baby who went to sleep with a butane heater on inside their tent while camping in Walhalla, Victoria;

An elderly woman who used an outdoor heater to warm her Surry Hills, NSW home.

Michael Perusco, NSW CEO of St Vincent de Paul said people were “thinking about being cold rather than being safe”.

“People are using these unusual methods to heat their homes. Electricity prices have risen sharply in recent years, and while they have steadied now, people are still reeling from that increase,” he said.

“When you’ve got high housing costs and high energy costs, it’s those on the lowest incomes that are hit hardest, and being forced to make very difficult choices to balance their budget – and sometimes, it’s impossible.”

The charity last year gave out $1.1 million in utilities vouchers to needy clients, and with projections forecasting this year’s total to be higher, called on the government to reform their energy assistance scheme for needy families.

Perusco said the state government’s flat rate $235 rebate for low-income households was ineffective, and called for government to pay a percentage of the total bill.

“It doesn’t take into account a larger family or people living in regional areas who are paying more in costs. This doesn’t cut it, and doesn’t make the level of difference it needs to.

“It’s disappointing in a nation as prosperous as ours that people are suffering in this way. We have the resources. It is imperative people have adequate housing and heating.”

NSW firefighters have been forced to ramp up their safety message with ‘Operation Cold Snap,’ visiting shopping centres, train stations, sporting fields and other community meeting places to warn people after the string of carbon monoxide poisonings.

“Every station in the state has been getting out and giving out information. Sometimes there is a lack of risk perception of how quickly a fire can develop and threaten life,” Whybro said.

“Raising awareness is part of our job, and it’s a shared responsibility between the fire service and the community. We try to do as much as we can, and one would hope people take notice.”